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 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
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package javax.swing.table;

import java.text.Collator;
import java.util.*;
import javax.swing.DefaultRowSorter;
import javax.swing.RowFilter;
import javax.swing.SortOrder;

/**
 * An implementation of <code>RowSorter</code> that provides sorting
 * and filtering using a <code>TableModel</code>.
 * The following example shows adding sorting to a <code>JTable</code>:
 * <pre>
 *   TableModel myModel = createMyTableModel();
 *   JTable table = new JTable(myModel);
 *   table.setRowSorter(new TableRowSorter(myModel));
 * </pre>
 * This will do all the wiring such that when the user does the appropriate
 * gesture, such as clicking on the column header, the table will
 * visually sort.
 * <p>
 * <code>JTable</code>'s row-based methods and <code>JTable</code>'s
 * selection model refer to the view and not the underlying
 * model. Therefore, it is necessary to convert between the two.  For
 * example, to get the selection in terms of <code>myModel</code>
 * you need to convert the indices:
 * <pre>
 *   int[] selection = table.getSelectedRows();
 *   for (int i = 0; i &lt; selection.length; i++) {
 *     selection[i] = table.convertRowIndexToModel(selection[i]);
 *   }
 * </pre>
 * Similarly to select a row in <code>JTable</code> based on
 * a coordinate from the underlying model do the inverse:
 * <pre>
 *   table.setRowSelectionInterval(table.convertRowIndexToView(row),
 *                                 table.convertRowIndexToView(row));
 * </pre>
 * <p>
 * The previous example assumes you have not enabled filtering.  If you
 * have enabled filtering <code>convertRowIndexToView</code> will return
 * -1 for locations that are not visible in the view.
 * <p>
 * <code>TableRowSorter</code> uses <code>Comparator</code>s for doing
 * comparisons. The following defines how a <code>Comparator</code> is
 * chosen for a column:
 * <ol>
 * <li>If a <code>Comparator</code> has been specified for the column by the
 * <code>setComparator</code> method, use it.
 * <li>If the column class as returned by <code>getColumnClass</code> is
 * <code>String</code>, use the <code>Comparator</code> returned by
 * <code>Collator.getInstance()</code>.
 * <li>If the column class implements <code>Comparable</code>, use a
 * <code>Comparator</code> that invokes the <code>compareTo</code>
 * method.
 * <li>If a <code>TableStringConverter</code> has been specified, use it
 * to convert the values to <code>String</code>s and then use the
 * <code>Comparator</code> returned by <code>Collator.getInstance()</code>.
 * <li>Otherwise use the <code>Comparator</code> returned by
 * <code>Collator.getInstance()</code> on the results from
 * calling <code>toString</code> on the objects.
 * </ol>
 * <p>
 * In addition to sorting <code>TableRowSorter</code> provides the ability
 * to filter.  A filter is specified using the <code>setFilter</code>
 * method. The following example will only show rows containing the string
 * "foo":
 * <pre>
 *   TableModel myModel = createMyTableModel();
 *   TableRowSorter sorter = new TableRowSorter(myModel);
 *   sorter.setRowFilter(RowFilter.regexFilter(".*foo.*"));
 *   JTable table = new JTable(myModel);
 *   table.setRowSorter(sorter);
 * </pre>
 * <p>
 * If the underlying model structure changes (the
 * <code>modelStructureChanged</code> method is invoked) the following
 * are reset to their default values: <code>Comparator</code>s by
 * column, current sort order, and whether each column is sortable. The default
 * sort order is natural (the same as the model), and columns are
 * sortable by default.
 * <p>
 * <code>TableRowSorter</code> has one formal type parameter: the type
 * of the model.  Passing in a type that corresponds exactly to your
 * model allows you to filter based on your model without casting.
 * Refer to the documentation of <code>RowFilter</code> for an example
 * of this.
 * <p>
 * <b>WARNING:</b> <code>DefaultTableModel</code> returns a column
 * class of <code>Object</code>.  As such all comparisons will
 * be done using <code>toString</code>.  This may be unnecessarily
 * expensive.  If the column only contains one type of value, such as
 * an <code>Integer</code>, you should override <code>getColumnClass</code> and
 * return the appropriate <code>Class</code>.  This will dramatically
 * increase the performance of this class.
 *
 * @param <M> the type of the model, which must be an implementation of <code>TableModel</code>
 * @see javax.swing.JTable
 * @see javax.swing.RowFilter
 * @see javax.swing.table.DefaultTableModel
 * @see java.text.Collator
 * @see java.util.Comparator
 * @since 1.6
 */
public class TableRowSorter<M extends TableModel> extends DefaultRowSorter<M, Integer> {

  /**
   * Comparator that uses compareTo on the contents.
   */
  private static final Comparator COMPARABLE_COMPARATOR =
      new ComparableComparator();

  /**
   * Underlying model.
   */
  private M tableModel;

  /**
   * For toString conversions.
   */
  private TableStringConverter stringConverter;


  /**
   * Creates a <code>TableRowSorter</code> with an empty model.
   */
  public TableRowSorter() {
    this(null);
  }

  /**
   * Creates a <code>TableRowSorter</code> using <code>model</code>
   * as the underlying <code>TableModel</code>.
   *
   * @param model the underlying <code>TableModel</code> to use, <code>null</code> is treated as an
   * empty model
   */
  public TableRowSorter(M model) {
    setModel(model);
  }

  /**
   * Sets the <code>TableModel</code> to use as the underlying model
   * for this <code>TableRowSorter</code>.  A value of <code>null</code>
   * can be used to set an empty model.
   *
   * @param model the underlying model to use, or <code>null</code>
   */
  public void setModel(M model) {
    tableModel = model;
    setModelWrapper(new TableRowSorterModelWrapper());
  }

  /**
   * Sets the object responsible for converting values from the
   * model to strings.  If non-<code>null</code> this
   * is used to convert any object values, that do not have a
   * registered <code>Comparator</code>, to strings.
   *
   * @param stringConverter the object responsible for converting values from the model to strings
   */
  public void setStringConverter(TableStringConverter stringConverter) {
    this.stringConverter = stringConverter;
  }

  /**
   * Returns the object responsible for converting values from the
   * model to strings.
   *
   * @return object responsible for converting values to strings.
   */
  public TableStringConverter getStringConverter() {
    return stringConverter;
  }

  /**
   * Returns the <code>Comparator</code> for the specified
   * column.  If a <code>Comparator</code> has not been specified using
   * the <code>setComparator</code> method a <code>Comparator</code>
   * will be returned based on the column class
   * (<code>TableModel.getColumnClass</code>) of the specified column.
   * If the column class is <code>String</code>,
   * <code>Collator.getInstance</code> is returned.  If the
   * column class implements <code>Comparable</code> a private
   * <code>Comparator</code> is returned that invokes the
   * <code>compareTo</code> method.  Otherwise
   * <code>Collator.getInstance</code> is returned.
   *
   * @throws IndexOutOfBoundsException {@inheritDoc}
   */
  public Comparator<?> getComparator(int column) {
    Comparator comparator = super.getComparator(column);
    if (comparator != null) {
      return comparator;
    }
    Class columnClass = getModel().getColumnClass(column);
    if (columnClass == String.class) {
      return Collator.getInstance();
    }
    if (Comparable.class.isAssignableFrom(columnClass)) {
      return COMPARABLE_COMPARATOR;
    }
    return Collator.getInstance();
  }

  /**
   * {@inheritDoc}
   *
   * @throws IndexOutOfBoundsException {@inheritDoc}
   */
  protected boolean useToString(int column) {
    Comparator comparator = super.getComparator(column);
    if (comparator != null) {
      return false;
    }
    Class columnClass = getModel().getColumnClass(column);
    if (columnClass == String.class) {
      return false;
    }
    if (Comparable.class.isAssignableFrom(columnClass)) {
      return false;
    }
    return true;
  }

  /**
   * Implementation of DefaultRowSorter.ModelWrapper that delegates to a
   * TableModel.
   */
  private class TableRowSorterModelWrapper extends ModelWrapper<M, Integer> {

    public M getModel() {
      return tableModel;
    }

    public int getColumnCount() {
      return (tableModel == null) ? 0 : tableModel.getColumnCount();
    }

    public int getRowCount() {
      return (tableModel == null) ? 0 : tableModel.getRowCount();
    }

    public Object getValueAt(int row, int column) {
      return tableModel.getValueAt(row, column);
    }

    public String getStringValueAt(int row, int column) {
      TableStringConverter converter = getStringConverter();
      if (converter != null) {
        // Use the converter
        String value = converter.toString(
            tableModel, row, column);
        if (value != null) {
          return value;
        }
        return "";
      }

      // No converter, use getValueAt followed by toString
      Object o = getValueAt(row, column);
      if (o == null) {
        return "";
      }
      String string = o.toString();
      if (string == null) {
        return "";
      }
      return string;
    }

    public Integer getIdentifier(int index) {
      return index;
    }
  }


  private static class ComparableComparator implements Comparator {

    @SuppressWarnings("unchecked")
    public int compare(Object o1, Object o2) {
      return ((Comparable) o1).compareTo(o2);
    }
  }
}
